EP2586703A1 - landing gear, aircraft and method - Google Patents

Abstract

The present invention relates to a landing gear (5) comprising at least one landing gear (10) comprising a landing gear leg (11) carrying at least one wheel (12). The landing gear (10) comprises a retraction cylinder (20) provided with an electric motor (23), an immobilization means (30) for locking the position of the retraction cylinder and for positioning the cylinder retraction into the "gear" position by gravity, first monitoring means (35) for monitoring the operation of the retraction cylinder (20), a first control means (65) of the retraction cylinder (20), and a second control means (75) of the immobilizing means (30).

Description

The present invention relates to an undercarriage, an aircraft provided with such an undercarriage and a method implemented by the undercarriage.

The invention is therefore in the technical field of landing gear, and more particularly aircraft landing gear capable of performing a vertical landing and in particular rotary wing aircraft. Indeed, the issue related to aircraft unsuitable for vertical landing differs from the problematic with aircraft landing vertically. Therefore, the term "rolled landing" a landing made by an aircraft, as opposed to a "vertical landing" that can be achieved by vertical landing aircraft such as helicopters.

Regardless of the nature of the aircraft, an undercarriage may comprise a plurality of landing gear provided with at least one wheel to allow evolutions of the aircraft on the ground until take-off, the damping of the resulting impact. landing, and with a braking system of stopping the aircraft over an acceptable distance.

The increase in the mass and speed of aircraft, together with the rise in vertical and horizontal kinetic energy to be absorbed on landing, has sometimes led to the gradual adoption of oleopneumatic dampers. In addition, braking systems are sometimes equipped with hydraulic controls.

In addition, the increased aerodynamic drag generated by the landing gear in flight has led to an increasing interest for retractable landing gear in flight in the fuselage of the aircraft. We understand that it is necessary to guarantee for reasons the exit of such a retractable landing gear from its housing prior to landing.

To achieve this goal, some systems provide redundancy of the landing gear output control to overcome a malfunction of an output control.

In this context, the manufacturers have implemented simple and safe hydraulic architectures to allow the rapid exit of a landing gear. Such an architecture comprises a landing gear hydraulic cylinder connected by pipes to a fluid reservoir and a hydraulic pump.

Conventionally, the fluid reservoir of a helicopter is located in an upper part of the aircraft, whereas on the contrary the landing gear is located in fact in a lower part of the aircraft. Pipes run from one end to another of the helicopter, this arrangement maximizing the risk of leakage, the mass of the device and the management of the cohabitation of the various hydraulic and / or electrical networks.

In addition, this architecture requires the use of many sensors to verify the proper functioning of the various organs implemented.

In order to achieve the safety objectives imposed by the certification regulations, the retraction cylinders are generally hydraulic linear cylinders. Hydraulic distributors are connected by pipes to the hydraulic linear retraction cylinders to require retraction or exit of the landing gear according to an input order, this input order can be a given order mechanically or electrically.

Hydraulic retracting cylinders are commonly used in that they offer optimized mass power. In addition, these hydraulic linear retraction cylinders have a low susceptibility to seizure phenomenon, this feature giving them an acceptable level of safety. The risk of seeing a linear hydraulic retraction cylinder oppose an emergency exit of a landing gear under the effect of its weight is in particular virtually zero.

Similarly, it is customary to implement a braking system using a hydraulic distributor controlled by pedals via either a mechanical link or a volumetric hydraulic transmission. This results in a problem of hydraulic piping installation from the hydraulic generating circuit to the cockpit level, and from the cockpit to the brakes.

From the moment when a servovalve was used for the regulation of the braking system that controlled the hydraulic pressure to an electric current, it seemed much simpler to directly supply this servovalve via the hydraulic generating circuit and to control its output pressure. by a current supplied by an electric transmitter actuated by the pedal.

Therefore, the state of the art has landing gear provided with a damper, a hydraulic retraction cylinder to enter and exit the landing gear of a train box, and a system of hydraulic braking.

This mainly hydraulic architecture has the advantage of being safe and effective. However, it requires the use of a large number of pipes, pumps, fluid reservoirs, and many sensors.

In addition, on a small aircraft such as a helicopter, it is not uncommon to implement piping from one end to another of the aircraft.

It is therefore understood that this hydraulic architecture is relatively heavy and bulky. In addition, the maintenance of the hydraulic architecture can be tricky, for example for leak detection whose sources can be, in fact, multiple.

Important tonnage aircraft architectures are known using electrical control means for controlling hydraulic retraction cylinders.

However, to meet the security requirements, it may be envisaged to double or even quadruple the control means used. The person skilled in the art then evokes "duplex" or "quadruplex" architectures.

Such architecture has a limited impact on large tonnage aircraft, in terms of mass. However, the impact in terms of mass seems prohibitive on a vertical landing aircraft having a low or a medium tonnage.

It should be noted that aircraft and helicopters and more generally landing aircraft including vertical have significant differences, the technical field rolled landing aircraft and the technical field of vertical landing aircraft then being distinct.

Indeed, a rolled landing aircraft such as an airliner has a very large mass compared to a small or medium sized vertical landing aircraft. In addition, a rolled landing aircraft has a much faster landing landing speed than a vertical landing aircraft.

These radical differences have led the helicopter manufacturers to adapt the landing gear as needed, unlike the aircraft manufacturers, both in their structure and in their order. Given the importance and mastery of hydraulics in the field of flight controls, this intrinsically available control device, moreover safe, was preferred to ensure the control of landing gear and brakes on the aircraft landing vertically.

Among the state of the art, the document is known FR 2,887,516 .

This document presents a communication network to which actuators for actuation, orientation and braking are connected.

The document FR 2 946 320 shows an aircraft braking system comprising an electromechanical actuator acting on a pusher, the pusher applying a braking force on a disk.

The document US 2009/0187293 has an architecture provided with a control module connected to proximity sensors of a landing gear and a control lever of said landing gear.

The document EP 2107273 has an undercarriage with a carriage leg carrying two wheels.

In addition, the undercarriage comprises a primary actuator for manipulating the landing gear leg from a "retracted train" position to a "gear" position and vice versa.

In addition, the undercarriage is provided with a device provided with an articulated connecting rod called "hinged stay" and a compass called "strut arrangement" which cooperates with a spring. This device makes it possible to block the undercarriage in the "out of the train" position.

As a result, the undercarriage comprises a second actuator for folding the compass to retract the landing gear using the first actuator.

We also know the document US 3224713 .

The present invention therefore aims to provide an undercarriage for a vertical landing aircraft, this landing gear being relatively light, simple and able to meet the safety objectives imposed by the certification regulations in force.

The term "rotary wing aircraft" means an aircraft that can notably and not necessarily exclusively perform a vertical landing.

According to the invention, an aircraft undercarriage and in particular an aircraft capable of performing a vertical landing comprises at least one landing gear, the landing gear comprising a landing gear leg carrying at least one wheel.

• un vérin de rétraction relié à la jambe de train, le vérin de rétraction étant muni d'un moteur électrique déplaçant un moyen mobile du vérin de rétraction par rapport à un moyen fixe du vérin de rétraction d'une position « train rentré » vers une position « train sorti » et de la position « train sorti » vers la position « train rentré » afin respectivement de sortir la roue d'une case de train et de rentrer ladite roue dans la case de train,
• un moyen d'immobilisation électrique ou mécanique pour verrouiller la position du moyen mobile par rapport au moyen fixe et pour permettre le positionnement du moyen mobile dans la position « train sorti » par gravité,
• un premier moyen de surveillance pour surveiller le fonctionnement du vérin de rétraction, le premier moyen de surveillance étant relié à un moyen d'affichage signalant la position du vérin de rétraction et l'état du moyen d'immobilisation,
• un premier moyen de commande du vérin de rétraction, et un deuxième moyen de commande du moyen d'immobilisation.

This landing gear is notably remarkable in that the landing gear comprises:

• a retraction cylinder connected to the landing gear leg, the retraction cylinder being provided with an electric motor moving a movable means of the retraction cylinder relative to a fixed means of the retraction cylinder from a "retracted" position to a position "out of the train" and the position "train out" to the position "retracted train" respectively to take out the wheel of a box of the train and to enter said wheel in the box train,
• an electrical or mechanical immobilization means for locking the position of the moving means relative to the fixed means and for positioning the moving means in the "gear" position by gravity,
• first monitoring means for monitoring the operation of the retraction cylinder, the first monitoring means being connected to a display means signaling the position of the retraction cylinder and the state of the immobilizing means,
• first control means of the retraction cylinder, and second means for controlling the immobilizing means.

Therefore, we get a "electric" lander simple, compact and lightweight.

Indeed, it is found that these characteristics make it possible to obtain a viable simplex electrical architecture for a vertical landing aircraft.

Therefore, the first control means can be linked to the retraction cylinder by a single first command line, and / or the second control means can be linked to the immobilization means by a single second command line.

As a result, the architecture implemented is an electrical architecture called "simplex". The undercarriage then makes it possible to eliminate the disadvantages of hydraulic architectures.

The retraction cylinder comprises an electric motor for extending or retracting the retraction cylinder to move the landing gear leg and therefore each wheel of the landing gear.

The use of such a reversible electric retraction actuator taken alone seems incompatible with the high safety requirements in force in aeronautics.

Similarly, an immobilization means taken alone seems incompatible with high security requirements.

However, this retraction cylinder and this immobilizing means are associated with a first monitoring means.

If a pilot finds before landing and thanks to the first monitoring means that the retraction cylinder does not operate optimally, the pilot can maneuver the immobilization means for the landing gear to leave his landing gear box. gravity.

The combination of a retraction cylinder, a means of immobilization and a first security means then makes it possible to meet the security requirements imposed without imposing a duplex or quadruplex architecture.

The use of the undercarriage can also be associated with emergency vertical landing procedures in the event of an incident, of the type known to those skilled in the art.

The undercarriage may further include one or more of the additional features that follow.

• d'un unique moyen de freinage comportant un actionneur électrique pour freiner chaque roue,
• d'un deuxième moyen de surveillance pour détecter un dysfonctionnement du moyen de freinage et le signaler à un pilote, ledit deuxième moyen de surveillance étant relié à un organe d'affichage signalant un dysfonctionnement,
• d'un troisième moyen de commande du moyen de freinage.

For example, the landing gear is also equipped with:

• a single braking means comprising an electric actuator for braking each wheel,
• second monitoring means for detecting a malfunction of the braking means and signaling it to a pilot, said second monitoring means being connected to a display member signaling a malfunction,
• a third control means of the braking means.

The third control means can be linked to the braking means by a single third command line,

The braking means may then comprise a disk and a brake lining cooperating with this disk, the actuator operating a pointer pressing the lining against the disk to brake the wheel.

The electric actuator can precisely adjust the position of the pointer in order to adjust the pressure of the lining on the disk so as to dose the braking.

It should be noted that a blocking device due to lack of electric current can block the pointer of the actuator in a current position, for example in a maximum braking position when the aircraft is on the ground.

In addition, a malfunction of the braking means before landing is detected by the second monitoring system and reported to a pilot.

For example, the second monitoring system comprises a pressure sensor. By correlating the position of the pointer with the measured pressure, a malfunction of the braking means can be determined and reported to a pilot.

The pilot warned of the malfunction can apply a strictly vertical landing procedure to avoid having to request a defective braking means.

As a result, the undercarriage makes it possible to meet the safety requirements according to a simplex electrical architecture.

According to another aspect, the immobilizing means comprises a brake for lack of current, the brake blocking the moving means of the retraction cylinder in the absence of electric current.

Alternatively, it is possible to provide a mechanical immobilization means.

Thus, under normal conditions, the electric current brake is not powered electrically by the second control means to immobilize the moving means of the retraction cylinder, and therefore the landing gear.

By cons, when the second control means is controlled to trigger the output of the landing gear, the second control means supplies electrical power to the immobilizing means. Under his own weight, the landing gear then leaves the train box.

Once out, it no longer electrically power the brake power failure that immobilizes the landing gear in the "out of gear" position.

Such a means of immobilization is simple and very safe.

In another aspect, the retraction cylinder may be a jack with a movable body. Therefore, the retraction cylinder comprises a stationary rod-type fixed means fixed to a wall of the landing gear compartment and a movable means of the cylinder body type attached to the landing gear leg.

As a preferred variant, the retraction cylinder may be a movable rod cylinder. Therefore, the retraction cylinder has a fixed means of the cylinder body type fixed to a wall of the landing gear compartment and a movable rod rod type attached to the landing gear leg.

The electric motor may comprise a stator and a rotor, this rotor being secured to a screw and cooperating with the immobilizing means. The movable means includes a jack rod comprising a nut arranged on the screw, the undercarriage comprising an anti-rotating means for detaching said nut from rotation of said screw so that a rotation of the screw induces a translation of the nut, the first monitoring means comprising a first limit sensor for detecting the arrangement of the cylinder rod in the "retracted" position and a second limit sensor for detecting the arrangement of the cylinder rod in the position "train out".

The anti-rotational means may be disposed between the nut and a cylinder body of the fixed means. According to an alternative variant, the alternating means can be arranged between a structure of the aircraft and the electric motor, to lock in rotation the cylinder rod while allowing a translational movement of the rod for example.

The retraction cylinder then makes it possible to meet the needs by allowing an extension movement and a retraction movement of the landing gear leg to pull out or retract the landing gear into the landing gear compartment.

Note that the first monitoring means may comprise a member external to the retraction cylinder to verify that the retraction cylinder is in the "out of position" position.

Furthermore, the first control means optionally includes a management body communicating with the first monitoring means and the electric motor of the retraction cylinder, the management member communicating with the display means.

This management member may for example prohibit the exit or retraction of the landing gear according to flight parameters. For example, if a landing gear retraction order is given by a pilot while the aircraft rests on the ground, the management body can ignore this order and report an error.

The management member may also represent a member of the first control means and control the exit or retraction of the landing gear according to flight parameters.

In addition, it is noted that the first control means may include a control system that can be operated by an individual, this control system being connected to the management member.

In another aspect, the first command line may include at least one data concentrator and a bidirectional link.

For example, to simplify the device, the management unit is connected to a front data concentrator communicating with a front landing gear via via a CAN bus before and with a rear data concentrator, the rear data concentrator communicating via a first rear CAN bus with a first landing gear and via a second rear CAN bus with a second rear landing gear.

The terms "front" and "rear" refer to the direction of elongation of the aircraft, from a rear end to a front end comprising the nose of the aircraft.

In addition, the third control line may comprise a control box interposed between the braking means and the third control means, the control box transmitting a braking command to said braking means according to the input commands from the third control means and a programmed braking logic.

Indeed, the undercarriage may include a first rear landing gear and a second rear landing gear provided with a braking means.

Each pilot then comprises a control member of the third control means by rear landing gear.

The control box then applies a pre-established braking logic according to the orders from the various control members.

In addition, the control box may include a self-test module to control the operation of the braking means before a landing, the self-test module may be a code segment programmed in a memory of the control box executable by a processor.

Furthermore, the undercarriage may comprise a fourth control means for controlling the ground braking means when the aircraft is stopped.

In addition to a lander, the invention also relates to a vertical landing aircraft provided with such a lander.

• on vérifie le bon fonctionnement du vérin de rétraction, un défaut de fonctionnement étant signalé à un pilote afin que le pilote utilise le deuxième moyen de commande pour sortir le train d'atterrissage par gravité,
• lorsque ledit atterrisseur comporte un moyen de freinage, on vérifie le bon fonctionnement du moyen de freinage, un défaut de fonctionnement étant signalé au pilote afin que le pilote entame une procédure d'atterrissage vertical ne nécessitant pas la mise en oeuvre du moyen de freinage.

Moreover, the invention also relates to a method implemented by such an undercarriage, during which, prior to landing:

• the correct operation of the retraction cylinder is verified, a malfunction being signaled to a pilot so that the pilot uses the second control means to release the landing gear by gravity,
• when said undercarriage comprises a braking means, it verifies the proper functioning of the braking means, a malfunction being reported to the pilot so that the pilot begins a vertical landing procedure does not require the implementation of the braking means.

• la figure 1, un schéma présentant les organes participant à la rétraction et à la sortie du train d'atterrissage,
• la figure 2, une coupe d'un vérin de rétraction incorporant un moyen d'immobilisation, et
• la figure 3, un schéma présentant les organes participant à au freinage d'une roue du train d'atterrissage.

The invention and its advantages will appear in more detail in the context of the description which follows, with exemplary embodiments given by way of illustration with reference to the appended figures which represent:

• the figure 1 , a diagram showing the members participating in the retraction and the exit of the landing gear,
• the figure 2 a section of a retraction cylinder incorporating an immobilizing means, and
• the figure 3 , a diagram showing the members participating in the braking of a wheel of the landing gear.

The elements present in several separate figures are assigned a single reference.

The figure 1 presents an aircraft 1 equipped with a landing gear 5. More particularly, the aircraft 1 is an aircraft capable of including a vertical landing.

This landing gear 5 comprises a plurality of retractable landing gear 10, three landing gear being represented on this landing gear. figure 1 to form a lift polygon of the aircraft on the ground.

Each landing gear 10 comprises a landing gear leg 11 provided with a shock absorber 13 and at least one wheel 12. In addition, the landing gear is equipped with a retraction cylinder 20 connected to the landing gear leg 11 to allow on request the return of the landing gear in a box 6 and the landing gear of this landing gear at least partially out of this box 6.

This retraction cylinder 20 is an electric retraction cylinder, the length of the retraction cylinder can be modified on request by an electric motor 23 and not by hydraulic means. Therefore, the electric motor 23 can retract the retraction cylinder 20 into a "retracted train" position to induce an arrangement of the landing gear in the landing gear compartment, and can extend the retraction cylinder 20 into a "gear" position. To induce an output of the landing gear wheel from the landing gear compartment 6. For this purpose, the electric motor can move a moving means of the retraction cylinder relative to a fixed means of this retraction cylinder.

In addition, the undercarriage comprises a means of immobilization 30 by landing gear for firstly immobilize the retraction cylinder in the "retracted train" and "out of the train" positions and, secondly, to allow the positioning of the landing gear. retraction cylinder in the "gear" position by gravity in an "emergency" situation.

This immobilizing means 30 is an electrical means cooperating with the retraction cylinder 20. For example, the immobilizing means 30 comprises a brake for lack of current arranged in the retraction cylinder 20 to immobilize a moving means of the retraction cylinder. , such as a cylinder rod.

In addition, the undercarriage includes a first monitoring means for verifying the operation of the retraction cylinder.

The figure 2 shows a section of a retraction cylinder 20 according to a preferred embodiment.

This retraction cylinder 20 is provided with a cylinder body 22 comprising a fixing means 22 'to a wall of a landing gear compartment. Therefore the cylinder body represents a fixed means of the retraction cylinder 20.

Conversely, the retraction cylinder is provided with a movable means, namely a cylinder rod 21 having a first end slidable inside the cylinder body 22 and a second end adapted to be fixed to a cylinder. train leg 11.

To move the moving means relative to the fixed means, the retraction cylinder includes an electric motor 23.

This electric motor 23 comprises a stator 23 'secured to the cylinder body and a rotor 23' secured to a screw 24 via a fastening device 28. The fixing device may include a pair of roller bearings or oblique contacts.

Therefore, the cylinder rod 21 is provided with a nut 25 traversed by the screw 24. Such a nut may be a satellite roller nut.

The undercarriage comprises an anti-rotating means 26 for separating the nut 25 from the screw 24 in rotation so that a rotation of this screw 24 induces a translation of the nut 25.

This anti-rotational means 26 can then be arranged between the nut 25 and the cylinder body 21. Other variants are nevertheless possible.

The retraction cylinder may further include two end-of-stroke dampers 27.

On the other hand, the first monitoring means 35 includes a first limit sensor 36 detecting the positioning of the moving means in the "retracted" position, and a second limit sensor 37 detecting the positioning of the moving means in the position "Train out".

In another aspect, the immobilizing means 30 is favorably inserted into the cylinder body 22.

This immobilizing means 30 comprises a brake 31 with no current able to block the rotor 23 "and therefore the cylinder rod when not electrically powered.

Thus, in the absence of electric current, the brake 31 immobilizes the rotor 23 "and thus freezes the position of the moving means relative to the fixed means of the retraction cylinder, namely the position of the cylinder rod 21 relative to the body of cylinder 22.

The brake 31 advantageously comprises two coils each able to unlock the retraction cylinder. A first coil allows retraction or extension of the retraction cylinder on action of the motor 23 in a normal mode, a second coil allowing the extension of the jack by gravity in a backup mode.

With reference to the figure 1 , the undercarriage comprises a first control means 65 for controlling the motor 23 of each retraction cylinder, these motors being powered electrically by an electrical generating means 100 of the aircraft.

The first control means then transmits an order to each engine.

This order can be transmitted by a single first command line to each engine. We mean by the expression "Not transmit a single first command line to each engine" that it is not necessary to redundant the means of communication between the first control means and each engine.

Thus, the first control means may comprise a management member 66 communicating with the first monitoring means 35 and the electric motor of the retraction cylinder of each landing gear, this management member 66 communicating with a display means 40 Such a management unit may be a unit provided with at least one processor and a memory for example.

In addition, the first control means 65 may include a control system 67 operable by a pilot, the control system 67 being connected to the management member 66.

The first command line 80 may then include at least one data concentrator and two-way wire links.

According to the preferred embodiment presented, the management unit 66 communicates via a CAN type bus with a front data concentrator 82, this forward data concentrator communicating with the power electronics 200 of a front landing gear via a CAN bus.

In addition, the front data concentrator 82 communicates with a rear data concentrator 83, this rear data concentrator 83 communicating with the power electronics 200 of a first rear landing gear via a CAN bus and with the electronics 200 of a second rear landing gear via another CAN bus.

Furthermore, the landing gear 5 comprises a second control means 75 for controlling each immobilizing means 30.

This second control means may comprise a single control line comprising two wires by immobilization means, a first wire directly connecting an immobilizing means while a second wire directly connects the immobilization means via the management member. 66.

The second control means 75 may comprise a backup battery 101 for supplying the immobilization means if necessary.

In flight, each landing gear is retracted into its landing gear compartment 6. The first end-of-travel sensor of each retraction cylinder indicates to the management member that the moving means is in the "retracted train" position. management unit retranscribing this information on the display means 40.

Similarly, a locking information of the landing gear relative to the state of the immobilizing means is displayed on the display means 40.

To verify this information, the management unit can activate the electric motors of each retraction cylinder. If the moving means remains in position, and therefore if the information from the first limit sensors remain unchanged, the management unit deduces that the immobilizing means is working properly.

In addition, if the landing gear output is required, for example via the control system 67, the management unit can check the relevance of the order by using information from ancillary organs of the aircraft, if necessary. .

By way of example, the management unit can ignore the output order if the aircraft is traveling at a forward speed greater than a threshold, while signaling the inconsistency to the pilot via the display means 40.

If the order is not considered inconsistent, the management unit 66 transmits an order of exit to each landing gear. When the power electronics 200 of each retraction cylinder receives an order of movement of the landing gear, the power electronics 200 of each retraction cylinder feeds the first coil of the brake 31 with a lack of associated current to unlock the jack of retraction.

Therefore, the power electronics of each retraction cylinder electrically feeds the associated motor 23 to generate the rotation of its rotor 23 ", the rotor 23" causing the rotation of the screw 24 of the retraction cylinder. This results in a translation of the movable means of the retraction cylinder.

When the moving means reaches the second end-of-travel sensor, this second end-of-travel sensor informs the power electronics 200 which stops the motor 23 and stops feeding the first coil. The retraction cylinder is blocked again.

It is understood that the retraction cylinder is a two-position cylinder, namely a "pulled out" position and a "retracted train" position.

This information can be confirmed by an external member 300, such as a push sensor cooperating with the landing gear in the "out of position" position.

According to the method implemented, if the landing gear is not out, namely if the outer member 300 is not actuated by For example, a malfunction is transmitted to the pilot, the management body requesting for this purpose the display means 40.

Note that "display means" means a single display means or a set of separate display means.

The pilot can then operate the second control means 75.

In the embodiment presented, the second control means 75 requests the management unit 66. This management unit can inhibit the backup deployment order in case of inconsistency, for example if the management body determines that the aircraft is on the ground. For this purpose, the management unit is arranged in series on the second control line 90 connecting the second control means to each immobilization means.

In an emergency mode, the second control means supplies the second brake coil 31 of each landing gear to unlock each retraction cylinder. The mass of each landing gear and in particular of the assembly comprising the landing gear leg and the wheel generates a traction force on each moving means. Each mobile means then translates under the effect of gravity only.

Once a landing gear out, it stops powering the second coil to lock the retraction cylinder in the "out of position" position.

For example, the management member 66 cuts off the power supply of the immobilizing means when it receives a signal from the external members 300, this management member functioning as a switch that can open or close an electrical circuit depending on the situation. .

In addition, at least two landing gear of the undercarriage each comprise a braking means 45 for braking at least one wheel of this landing gear.

For example, a first landing gear and a second rear landing gear distributed on either side of an anteroposterior plane of symmetry each comprises a braking means.

Therefore, it is possible to control the evolutions on the ground of the aircraft using the brakes. By braking the wheels of a single rear landing gear, we can actually rotate the aircraft.

Each braking means 45 may comprise an electric actuator 46 for moving a brake lining with respect to a braking disc integral in rotation with the wheels of the landing gear.

In addition, each landing gear may comprise a second monitoring means 50 for monitoring the operation of the braking means.

In addition, each braking means may comprise an immobilizer of the electric actuator of each braking means for maintaining a braking pressure, such as an organ due to lack of current.

With reference to the figure 3 a third control means 70 makes it possible to control the braking exerted.

For example, the third control means comprises a control member 71 per pilot and braking means, four control members 71 for a pilot and a co-pilot according to the embodiment shown.

A third control line 85 then connects each control member to the braking means, the third control line comprising a control box 88.

For example, each control member is connected to a data concentrator 82 by a CAN bus, the data concentrator 82 being connected to the control box 88 by another CAN bus. This control box 88 is then connected to each braking means, in particular to each actuator 45 and to the second monitoring means 50 of the braking means.

In addition, the control box is electrically powered by an electric generator 100.

In addition, the control box can communicate with a management means, such as the management body 66 sometimes referred to as "aircraft management computer" in English.

This control box may comprise at least one processor and a memory, the processor controlling the braking means according to a logic preprogrammed in the memory.

Furthermore, the control box may include a self-test module 89 able to control the braking means before landing, the self-test module may be a code segment of a software for example.

Finally, the braking system includes a fourth control means 90 powered by an electrical generating means 100 and able to communicate with the control box.

For example, the fourth control means 90 transmits the electrical power to the control box 88 for the ground. require maximum braking of the wheels. Such fourth control means 90 is sometimes referred to as "parking brake".

Consequently, before landing, the self-test module 89 checks the operation of the braking means.

For example, this module 89 requires a displacement of the calibrated actuator 45 to generate a predetermined pressure of the brake lining on the brake disc. If the second monitoring means does not detect the correct pressure, the control box 88 informs the management member 66 which informs the pilot by a display member 60.

The pilot then starts a vertical landing procedure so as not to solicit potentially defective braking means.

Other known monitoring methods are conceivable.

On the other hand, when the third control means 70 issues a braking command, this braking command is transmitted to the control unit 88.

The order may optionally be transmitted to the management unit 66 for verification. Thus, the management member 66 can inhibit the braking command if this braking command proves to be inappropriate. For example, the management unit can inhibit or modify an asymmetrical and violent braking command that risks inducing yawning of the aircraft when the aircraft is traveling at a relatively high speed on the ground.

In the event that a valid braking command is transmitted to the control unit 88, this control box 88 controls the electric actuators 45 according to the preprogrammed logic.

On the ground and possibly aircraft stopped, it is also possible to brake the wheels using the fourth control means 90.

If an individual maneuvers the fourth control means 90, the fourth control means 90 orders the control unit 88 to exert maximum braking, or even to block the braking means in a position generating maximum braking.

Naturally, the present invention is subject to many variations as to its implementation. Although several embodiments have been described, it is well understood that it is not conceivable to exhaustively identify all the possible modes. It is of course conceivable to replace a means described by equivalent means without departing from the scope of the present invention.

Claims (14)

Landing landing gear (1) having at least one landing gear (10), the landing gear (10) comprising a landing gear leg (11) carrying at least one wheel (12),
characterized in that said landing gear (10) comprises: a retraction cylinder (20) connected to the landing gear leg (11), the retraction cylinder (20) being provided with an electric motor (23) displacing a moving means (21) of the retraction cylinder with respect to a fixed means (22) of the retraction cylinder from a "retracted train" position to a "gear" position and from the "gear" position to the "retracted gear" position respectively for pulling said wheel (12) out of position. a box of the train and to enter said wheel (12) in the train box, an immobilizing means (30) for locking the position of the moving means (21) relative to the fixed means (22) and for positioning the moving means (21) in the "gear" position by gravity, first monitoring means (35) for monitoring the operation of the retraction cylinder (20), said first monitoring means (35) being connected to a display means (40) signaling the position of the retraction cylinder and the state of the immobilization means, - a first control means (65) of the retraction cylinder (20), and a second control means (75) of the immobilizing means (30). Lander according to claim 1,
characterized in that said landing gear (10) comprises: a single braking means (45) comprising an electric actuator (46) for braking each wheel (12), a second monitoring means (50) for detecting a malfunction of the braking means (45), said second monitoring means (50) being connected to a display member (60) signaling a malfunction, - A third control means (70) of the braking means (45). Lander according to claim 1,
characterized in that the first control means (65) is connected to the retraction cylinder (20) by a single first control line (80), and / or the second control means (75) is connected to the immobilization means (30) by a single second control line (90) and / or a third control means (70) is connected to a braking means by a single third control line (85). Lander according to any one of claims 1 to 3,
characterized in that said immobilizing means (30) comprises a brake (31) lack of current, said brake (31) blocking the moving means in the absence of electric current. Lander according to any one of claims 1 to 4,
characterized in that said electric motor (23) comprises a stator (23 ') and a rotor (23 "), said rotor (23") being integral with a screw (24) and cooperating with said immobilizing means (30). ), said moving means comprises a cylinder rod (21) provided with a nut (25) arranged on said screw (24), said landing gear comprising an anti-rotating means (26) for detaching in rotation said nut from said screw so that a rotation of the screw induces a translation of the nut, said first monitoring means (35) comprising a first end-of-travel sensor (36) for detecting the arrangement of the cylinder rod (21) in the "retracted gear" position And a second limit sensor (37) for detecting the arrangement of the cylinder rod (21) in the "out of position" position. Lander according to any one of claims 1 to 5,
characterized in that said first monitoring means (35) comprises an outer member (300) to the retraction cylinder to verify that said retraction cylinder is in the "out of position" position. Lander according to any one of claims 1 to 6,
characterized in that said first control means (65) includes a management member (66) communicating with the first monitoring means (35) and the retraction actuator electric motor, said management member (66) communicating with said means display (40). Lander according to claim 7,
characterized in that said first control means (65) includes a control system (67) maneuverable by an individual, said control system (67) being connected to said management member (66). Lander according to any one of claims 1 to 8,
characterized in that said first command line (80) comprises at least one data concentrator (82) and a bidirectional link (81). Lander according to claim 2,
characterized in that a third control line (85) has a control box (88) interposed between said braking means (45) and said third control means (70), said control box (88) transmitting an order braking means to said braking means (45) according to the input commands from said third control means (70) and a programmed braking logic. Lander according to claim 10,
characterized in that said control box (88) includes a self-test module (89) for controlling the operation of the braking means (45) prior to a landing. Lander according to claim 2,
characterized in that it comprises a fourth control means (90) for controlling the braking means (45) on the ground so that the braking means exerts maximum braking. Aircraft (1) with vertical landing,
characterized in that it comprises a landing gear (5) according to any one of claims 1 to 12. Method implemented by a lander (5) according to any one of claims 1 to 12, during which, prior to landing: - the correct functioning of each retraction cylinder (20) is verified, a malfunction being signaled to a pilot so that the pilot uses the second control means (75) to lift the landing gear (10) by gravity, when said undercarriage comprises braking means, each braking means (45) is checked for proper operation, a malfunction is signaled to the pilot so that the pilot initiates a vertical landing procedure that does not require the implementation of the braking means (45).

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